1. Field of the Invention
The present invention relates to the structure for cleaning a print head of an ink jet printer and a device for driving the cleaning structure.
The present invention is based on Japanese Patent Applications No. Hei. 10-18657 and Hei. 10-339052, which are incorporated herein by reference.
2. Description of the Related Art
In the ink jet printer, liquid ink is supplied from an ink tank to a print head, and forcibly discharged in the form of an ink droplet onto a printing medium, through ink jet nozzles of the print head. Sometimes, one of some of the ink passages ranging from the ink tank to the ink jet nozzles are clogged with air bubbles to possibly obstruct the ink discharging through the passage. To cope with this, the ink jet printer usually has a xe2x80x9cclogging-check-pattern printing functionxe2x80x9d, and a xe2x80x9ccleaning functionxe2x80x9d. When the former function is exercised, the printer prints a preset clogging check pattern by use of all the nozzles of the print head. A user checks the printed preset pattern to locate a clogged nozzle or nozzles if such defective nozzle is present. The latter function, or the cleaning function, is exercised when the clogged nozzle is located, to suck ink from the clogged nozzle to remove its clogging.
Most of the ink jet printers are designed so as to be capable of printing in monocolor or multi-color mode. To this end, the printer uses four (K (black), C (cyan), M (magenta), Y (yellow)) or larger number of color inks. Further, the printer includes ink tanks and a set of nozzles (e.g., 64 or 128 nozzles), which are respectively provided for those color inks. In a printer using four color inks and having 64 nozzles for each color, the total number of required nozzles is 256, and greater.
The clogging check pattern printed out shows the location of a clogged nozzle, if present. Therefore, the user knows which of those nozzles arrayed is clogged. In the event that at least one nozzle is clogged, the user instructs the printer to exercise the cleaning function for removing the clogging. The cleaning operation usually consists of three steps; 1) xe2x80x9cflushingxe2x80x9d for driving the nozzle to discharge the ink, 2) xe2x80x9cwipingxe2x80x9d for wiping out the ink from the nozzle surface, and 3) xe2x80x9csuctionxe2x80x9d for sucking the ink from the nozzles by applying negative pressure to the nozzle. Thus, the cleaning operation is complicated. Of those cleaning operation steps, the xe2x80x9csuctionxe2x80x9d process is performed such that 1) the print head is moved to a home position, 2) the entire print surface of the print head is capped with a rubber cap, and 3) the ink is sucked from all the nozzles of the print head thus capped.
As described above, in the event of clogging of the nozzle, to remove the clogging, all the nozzles must be subjected to the suction process although the clogged nozzle is located. Some reasons are present for this. One of the reasons follows. The capping is formed through a complicated mechanism. Therefore, if only the clogged nozzle is sucked, the clogging is not always removed. If so, a natural conclusion is that the sucking of all the nozzles will reliably remove the clogging of the nozzle. However, the sucking of all the nozzles leads to consumption of much ink. The cost of the ink consumption is for the user to bear.
Some places where air bubbles are likely to stay are present in the ink passage ranging from the ink tank to the ink jet nozzle. One of the places is a filter chamber located downstream of and near to the ink tank. In case where a replaceable, ink cartridge is used for the ink tanks, the filter chambers are provided with needle tubes. When the ink cartridge is set to the printer, the needle tubes are thrust into the related ink tanks. During the thrusting, air bubbles possibly enter the filter chamber through a cylinder-piston action by the ink tank and the needle tube.
Generally, one ink tank supplies ink to a number of ink jet nozzles, and an ink supply passage is branched at a location downstream of the filter chamber to have a number of ink passages. The branching of the ink supply passage leads to an increase of its cross section area. The result is that an ink flow rate in each branched ink passage is reduced, and the force acting to drive the air bubbles out of the filter chamber is weak or insufficient.
Accordingly, an object of the present invention is to minimize the amount of ink consumed by the process of cleaning the ink jet nozzles.
Another object of the invention is to effectively drive air bubbles out of the filter chamber through the branched ink supply passages.
According to one aspect, there is provided an ink jet printer comprising: at least one ink chamber; a print head having a plurality of ink jet nozzles and being connected to the ink chamber; a print controller for driving the print head in order to print; and a capping device for covering the ink jet nozzles of the print head.
The capping device comprises: a cap component having a plurality of cavities for sorting the ink jet nozzles into a plurality of nozzle groups by ink chamber unit, thereby capping all ink jet nozzles corresponding to at least one ink chamber by nozzle group unit; at least one pipe being connected to the cavities of the cap component for supplying negative pressure to the cavities; and a suction controller for controlling the supply of the negative pressure through the pipe to the cavities, thereby supplying the negative pressure independently by every cavity, whereby the suction controller sucks the ink from the ink jet nozzles independently by the nozzle group unit.
In a preferred embodiment of the ink jet printer, the suction controller supplies the negative pressure to one arbitrary cavity of the cap component so as to suck the ink from the ink jet nozzles independently by the nozzle group unit, and all remaining cavities which correspond to one common ink chamber with the arbitrary cavity are sealed.
In another embodiment, the suction controller supplies the negative pressure to all the cavities corresponding to one common ink chamber simultaneously.
In yet another embodiment, a plurality of the ink chambers are provided in the printer, and the cap component has a dimension and number of cavities for capping all of the ink jet nozzles connected to all ink chambers.
In still another embodiment, the cap component comprises one of an integral unit and a plurality of sub-units divided according to the nozzle groups sorted by the ink chamber unit.
In a further embodiment, a plurality of the ink chambers are provided in the printer, and the cap component does not have a dimension and number of cavities for capping all of the ink jet nozzles connected to all ink chambers, and the ink jet printer further comprising a second cap component capping all of the ink jet nozzles at a stretch.
In a still further embodiment, a plurality of the nozzle groups are arranged in a recording medium transporting direction.
In another embodiment, the cap component includes the number of chambers equal to that of the nozzle groups, and caps all the nozzle groups of the print head simultaneously.
In yet another embodiment, one nozzle group is divided into at least two sub-groups of nozzle (in an extreme case, one sub-group consists of one nozzle), and the cap component includes at least two cavities and simultaneously caps those sub-groups.
In still another embodiment, pipes connected to the cavities include valves for closing and opening the pipes. By selectively opening the valves, ink is selectively sucked from the nozzle groups.
In a further embodiment, the pipes connected to the cavities include negative pressure sources, independently operable.
In an additional embodiment, two or larger number of the nozzle groups of the print head are connected to one ink chamber. The cap component includes two or larger number of the cavities so as to simultaneously cap two or larger number of the nozzle groups connected to one ink chamber. Negative pressure is selectively supplied to those cavities. At this time, the remaining cavities are closed (by closing the valves of the pipes associated therewith or applying low negative pressure thereto), thereby preventing air bubbles from entering the remaining nozzle groups.
In another embodiment of the ink jet printer, at least two nozzle groups of the print head are connected to one chamber, and ink is sucked from the two or larger number of nozzle groups connected to the chamber.
In an additional embodiment, the suction controller includes a selective suction portion for supplying negative pressure to one cavity selected from the cavities, and an all-nozzle suction portion for supplying negative pressure to all of the cavities.
In another embodiment, the suction controller includes a selective suction portion for supplying negative pressure to one cavity selected from the plural number of cavities so as to suck ink from the selected cavity, and an all-nozzle suction portion for supplying negative pressure to all of the cavities so as to suck ink from all of the cavities.
In yet another embodiment, the suction controller controls the supply of negative pressure in accordance with clogged nozzle information indicative of a location of a clogged nozzle.
In still another embodiment, the clogged nozzle information includes information indicative of the ink chamber connected to a clogged nozzle, the number of clogged nozzles, and a location of the clogged nozzle on the print head.
In an additional embodiment of the ink jet printer, the suction controller includes a selection table containing a plural number of control guidance corresponding to a variety of clogged nozzle information, and controls the supply of negative pressure in accordance with a specific control guidance, which correspond to the clogged nozzle information, selected from the selection table.
In a further embodiment, the suction controller selects a selective suction mode or an all-nozzle suction mode in accordance with the clogged nozzle information received, and when the selective suction mode is selected, the suction controller sucks ink from at least one nozzle group selected from the plural number of nozzle groups, and when the all-nozzle suction mode is selected, the suction controller simultaneously sucks ink from all of the nozzle groups.
Further, the print controller may include a check pattern print portion for printing a predetermined clogging check pattern used for locating a clogged nozzle by driving the print head.
The ink jet printer may further comprises pattern reading means for reading a printed clogging check pattern to locate a clogged nozzle and to send resultant clogged nozzle information to the suction controller.
The ink jet printer may further comprise input means, operated by a user, for entering clogged nozzle information to the ink jet printer.
In a further embodiment, the ink jet printer is connected to a host controlling device, and the suction controller receives clogged nozzle information from the host controlling device.
In the ink jet printer, the suction controller receives information designating a specific nozzle group or a specific chamber, and supplies negative pressure to a chamber associated with the specific nozzle group or the specific chamber in accordance with the designating information.
The ink jet printer is connected to a host controlling device, and the suction controller receives the designating information from the host controlling device.
According to another aspect of the invention, there is provided a printing system including an ink jet printer and a host controlling device for controlling the ink jet printer. The ink jet printer is constructed described above, and sucks ink from the nozzles of the print head every nozzle group. The host controlling device sends to the ink jet printer selection information necessary for selecting a nozzle group to be sucked from the nozzle groups.
In a preferred embodiment of the printing system, the host controlling device includes a commanding portion for commanding the ink jet printer to print a predetermined clogging check pattern, a user input means by which a user enters user input information indicative of clogged nozzle information, and a selection information generator for generating the selection information on the basis of the user input information entered by the user interface.
In another embodiment of the printing system, the user interface displays a clogging check pattern image on a user interface screen of the host controlling device, and the user enters the user input information by pointing a location on the displayed clogging check pattern image, which corresponds to the location of the clogged nozzle.
According to a further aspect of the invention, there is provided a data storing medium, accessible by a computer, storing a program for executing a process to detect a defective dot forming element of those dot forming elements in a printer, wherein the process comprising the steps of: instructing the printer to print a predetermined clogging check pattern; displaying a clogging check pattern image on a user interface screen of the computer; and specifying the defective dot forming element in a manner that the user points to a location in the displayed clogging check pattern, which corresponds to the defective dot forming element.
According to an additional aspect of the invention, there is provided a data storing medium, accessible by a computer, storing a program for executing a process to instruct an ink jet printer having a number of ink jet nozzles to clean the nozzles, wherein the ink jet printer selectively performs an ink saving cleaning process or a normal cleaning process, the ink saving cleaning process is executed through a selective suction operation to suck ink from only at least one nozzle selected from the ink jet nozzles at any time, and the normal cleaning process is executed through a all-nozzle suction operation for simultaneously sucking ink from all of the ink jet nozzles, and the cleaning instruction process includes a step of displaying an image requesting a user to select the ink saving cleaning process or the normal cleaning process on a user interface screen of the computer, a step of instructing the ink jet printer to execute the ink saving cleaning process or the normal cleaning process selected, by the user, on the user interface screen of the computer.
According to an additional aspect of the invention, there is provided a control method for an ink jet printer having a print head having a number of ink jet nozzles sorted into a plural number of nozzle groups, and a capping device for selectively sucking ink from the nozzle groups by selectively capping the nozzle groups, comprising the steps of: printing a predetermined clogging check pattern and causing a user to locate a clogged nozzle or nozzles; visually presenting a clogging check pattern to the user; obtaining information indicative of the clogged nozzle in a manner that the user points to a location in the displayed clogging check pattern, which corresponds to the clogged nozzle in the printed clogging check pattern; selecting one nozzle group from the nozzle groups on the basis of the clogged nozzle information obtained; and sucking ink from the selected nozzle group.
As well known, a computer program implementing the present invention may be installed in or loaded into the computer by any of various media, e.g., the disk storage, the semiconductor memory, and the communication line.
Features and advantages of the invention will be evident from the following detailed description of the preferred embodiments described in conjunction with the attached drawings.